The present invention relates to a novel and improved piston and cylinder for handling fluids such as liquids and gases, and more particularly relates to a piston pump which is particularly suited for purposes of retrieving samples of gaseous products without contamination, for example, by pump oil, for purposes of analysis. Other applications of the present improved apparatus are possible where small pressures need be developed, and the present apparatus is especially applicable where miniaturization of parts is desired, and indeed, the fluid handling apparatus is adaptable for valve structures or other uses requiring a reciprocating member to move in sealed relation to its housing.
One of the common problems associated with reducing the size of and number of parts for pumps has been the need for precision bearings and seals as found in the conventional pump. Furthermore, natural wear and tear deteriorates the component parts of the pump and replacement of standard bearings and seals is both difficult and expensive in most instances. Another problem arises due to non-uniform thermal expansion of the various working parts of the assembly.
The pump, and particularly the cylinder block and piston assembly, according to the present invention, removes these disadvantages by avoiding the need for internal piston rings. Further, as the piston and piston cylinder become worn, means are provided to maintain the necessary sealing contact so that maintenance problems are minimized. Also, because of the flexible nature of the piston cylinder seal, the problem of piston cylinder binding due to differential thermal expansion is avoided. Finally, the present invention avoids many of the problems in the prior art by greatly reducing the number of working parts of the apparatus so that a simplified pump is provided which is inexpensive to manufacture.